What term describes a rock formation that allows water to move through, such as sandstone, and must occur above a layer that prevents seeping away?

What term describes a rock formation that allows water to move through, such as sandstone, and must occur above a layer that prevents seeping away?

• A. Aquifer
• B. Confluence
• C. Sheetwash
• D. Watershed

Answer: (A)

Groundwater moves through permeable rock that stores and transmits water—that rock is called an aquifer. Sandstone is a common example because its interconnected pore spaces let water flow through. An aquifer sits beneath an impermeable or much less permeable layer (an aquitard or confining bed) that prevents water from seeping away, helping to trap and contain the groundwater. Sometimes the aquifer is open to the surface below a water table (unconfined), and other times it’s trapped between impermeable layers (confined), but in either case the key idea is a rock formation that allows water to move through while being beneath a seal that stops vertical leakage. Confluence describes where two streams meet, sheetwash is surface runoff moving over the ground, and watershed is the land area that drains to a common outlet—these terms don’t describe the subsurface, permeable rock that stores and transmits groundwater.

Groundwater moves through permeable rock that stores and transmits water—that rock is called an aquifer. Sandstone is a common example because its interconnected pore spaces let water flow through. An aquifer sits beneath an impermeable or much less permeable layer (an aquitard or confining bed) that prevents water from seeping away, helping to trap and contain the groundwater. Sometimes the aquifer is open to the surface below a water table (unconfined), and other times it’s trapped between impermeable layers (confined), but in either case the key idea is a rock formation that allows water to move through while being beneath a seal that stops vertical leakage.

Confluence describes where two streams meet, sheetwash is surface runoff moving over the ground, and watershed is the land area that drains to a common outlet—these terms don’t describe the subsurface, permeable rock that stores and transmits groundwater.